The present disclosure generally relates to a container for storing a medical or pharmaceutical liquid, in particular for storing an insulin preparation, which is administered to a patient by, for example, an infusion pump. Further the present disclosure generally relates to a dosing apparatus for dosing a predetermined amount of liquid from the container and a device for automated release of the medical or pharmaceutical liquid from the container.
Devices for the automated release of medical or pharmaceutical liquids are normally used with patients who have a continuous and, in the course of the day, varying need of medicine, which can be administered by subcutaneous or intravenous infusion. Some applications are, for example, certain pain therapies and the treatment of diabetes, in which computer controlled infusion pump devices, such as insulin pumps, are used. Such devices can be carried by a patient on the body and contain a certain amount of liquid medicine in a liquid reservoir, for example, in the form of a container. The liquid reservoir often comprises medicine sufficient for several administrations on one or several days. Such a device may comprise a dosage unit or is connected to a dosing unit for controlling the required amount of liquid and providing it for administration. The administration may be continuous or a repeated dispense of predetermined amounts of liquid. The liquid medicine is supplied to the patient's body from the medicine reservoir through an infusion cannula or an injection needle. Additional tubing may be present between liquid reservoir and cannula or needle.
Infusion devices are, for example, a modular infusion pump device or an infusion device with a down stream pump system. One system for the delivery of a substance can have a dosing unit for withdrawal of a specified amount of liquid from a reservoir, for example, in the form of a cartridge or a bag. The system uses the same opening for bringing in the liquid amount from the reservoir and for administering the same to a patient. Another system can have a fluidic assembly comprising a dosing unit and a drug reservoir for an ambulatory infusion device. The dosing unit comprises a charging and discharging valve system, wherein the drug reservoir is in fluid connection with an inlet valve thereof. The drug reservoir may be realized as a cartridge, a bag, a pouch or the like.
Particularly in self-administration medicine, for example, insulin, the patients using the medicine in question and administering it themselves by an infusion pump are increasingly emphasizing convenience and discretion. As a consequence, the dimensions of such infusion devices are limited, and, in particular, the overall length, width and thickness should be as small as possible in order not be evident through clothing and to be carried as comfortably as possible.
While there are fully or partly disposable single-use infusion pump devices, such devices are typically non-disposable and are loaded with a disposable drug reservoir. As drug reservoirs, rigid containers like cartridges are commonly used. Also flexible containers like bags are suitable, which may comprise two flexible wall sheets sealed together or one flexible sheet in combination with a rigid shell. Disposable containers are preferable for sterility and contamination-prevention reasons. They may be delivered pre-filled with a certain medical or pharmaceutical liquid, or empty, ready to be filled by a user. Self-filling of containers has the advantage that medicines that are not readily available in prefilled containers can be used in infusion pump devices, thereby providing the patient with a larger choice of sources for his medicines. Furthermore, the stability of many medicine in liquid form, particularly in plastic containers, is limited.
Flexible containers have the advantage of a smaller volume surplus of the container in relation to its content, which reduces the costs of manufacture and the achievable dimensions of an infusion pump device. For use in an infusion pump device, a flexible container is connected to a conduit system of the device, especially to a dosage unit of the device. For that purpose the flexible container may be provided with a port. Such a port can be mounted an the container with a flange sealed to a container wall sheet. Or, a port in the form of a flexible tube or rigid connection piece welded between two sheets of the container at the periphery of the flexible container may be used.
A medical device using a flexible container can house a flexible drug reservoir with a port closed by a septum that is punctured by a hollow needle of the conduit system of the infusion pump device. An infusion device comprising a fluid reservoir made of a rigid bladder shell and a non-distensible bladder film welded thereto where the content of the reservoir is dispensed by a spring force through one or more flow paths in fluid connection to the reservoir.
A common problem of flexible containers with ports is the dead volume remaining between the collapsed container and the port. Thus, complete drainage of the contents of a flexible container is not possible. For a single-use container filled with the medicine, the dead volume considerably increases the effective cost per dose and thus of the overall therapy cost. Additionally the dead volume leads to an increase of the overall volume of the flexible container, and thus of an infusion pump device that utilizes such a flexible container.
A further problem, particularly of flexible containers as they are known, is air remaining in the container. If, for example, a flexible container is provided empty and is intended to be filled with the appropriate medicament by the user himself, the dead volume is initially filled with air. However, removing the air from flexible containers will require a certain skill level of a user. In addition to air resulting from the dead volume of the container, some amount of air may enter the container when being filled, typically by a user prior to usage, as described above.
Furthermore, many drugs and in particular insulin are typically stored at low temperature, for example, in a refrigerator. When being used in an administration device or infusion device at a higher temperature, such as room or body temperature, air that is initially solved in the liquid outgases, resulting in air bubbles inside the container.
In current devices, air bubbles may be administered instead of the liquid medicine, which leads to potentially dangerous dosing errors. Furthermore the administration of air into a patient's body should generally be avoided for medical reasons.
Furthermore, most devices monitor a pressure or force applied during drug release by a drive in order to detect the presence of fluidic occlusions or blockages. Due to the negligible compressibility of liquids, the fluidic pressure tends to show a steep increase in such situations. Air or generally gas, however, has a high compressibility and therefore drastically reduced the fluidically stiffness. Therefore, the pressure increase and the detection of occlusions or blockages are largely delayed.
Often the problems of dead volume areas and air remaining in the container amplify each other when a container is orientated in an unfavorable position; for example, when a port is located in an upper part while liquid converges in a lower part of the container such that a fluid connection between port and liquid is interrupted.
Therefore, there is a need for a container for storing medical or pharmaceutical fluid, which enables save discharge of fluid from the container, largely avoids administration of air from the container, guarantees easy handling and safe storage of liquid within the container, offers high flexibility and convenience for a patient using the container, and is produced at low cost, which improves precise dosing of liquid, is easy to handle and may be produced cost-efficient and which enables simple maintenance and handling, improves liquid administration of precise dosages, and offers comfortable usage for a patient.